vfs_mountroot.c revision 288091 
1/*-
2 * Copyright (c) 2010 Marcel Moolenaar
3 * Copyright (c) 1999-2004 Poul-Henning Kamp
4 * Copyright (c) 1999 Michael Smith
5 * Copyright (c) 1989, 1993
6 *      The Regents of the University of California.  All rights reserved.
7 * (c) UNIX System Laboratories, Inc.
8 * All or some portions of this file are derived from material licensed
9 * to the University of California by American Telephone and Telegraph
10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
11 * the permission of UNIX System Laboratories, Inc.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 * 1. Redistributions of source code must retain the above copyright
17 *    notice, this list of conditions and the following disclaimer.
18 * 2. Redistributions in binary form must reproduce the above copyright
19 *    notice, this list of conditions and the following disclaimer in the
20 *    documentation and/or other materials provided with the distribution.
21 * 4. Neither the name of the University nor the names of its contributors
22 *    may be used to endorse or promote products derived from this software
23 *    without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 */
37
38#include "opt_rootdevname.h"
39
40#include <sys/cdefs.h>
41__FBSDID("$FreeBSD: head/sys/kern/vfs_mountroot.c 288091 2015-09-22 03:34:07Z bdrewery $");
42
43#include <sys/param.h>
44#include <sys/conf.h>
45#include <sys/cons.h>
46#include <sys/fcntl.h>
47#include <sys/jail.h>
48#include <sys/kernel.h>
49#include <sys/malloc.h>
50#include <sys/mdioctl.h>
51#include <sys/mount.h>
52#include <sys/mutex.h>
53#include <sys/namei.h>
54#include <sys/priv.h>
55#include <sys/proc.h>
56#include <sys/filedesc.h>
57#include <sys/reboot.h>
58#include <sys/sbuf.h>
59#include <sys/stat.h>
60#include <sys/syscallsubr.h>
61#include <sys/sysproto.h>
62#include <sys/sx.h>
63#include <sys/sysctl.h>
64#include <sys/sysent.h>
65#include <sys/systm.h>
66#include <sys/vnode.h>
67
68#include <geom/geom.h>
69
70/*
71 * The root filesystem is detailed in the kernel environment variable
72 * vfs.root.mountfrom, which is expected to be in the general format
73 *
74 * <vfsname>:[<path>][	<vfsname>:[<path>] ...]
75 * vfsname   := the name of a VFS known to the kernel and capable
76 *              of being mounted as root
77 * path      := disk device name or other data used by the filesystem
78 *              to locate its physical store
79 *
80 * If the environment variable vfs.root.mountfrom is a space separated list,
81 * each list element is tried in turn and the root filesystem will be mounted
82 * from the first one that suceeds.
83 *
84 * The environment variable vfs.root.mountfrom.options is a comma delimited
85 * set of string mount options.  These mount options must be parseable
86 * by nmount() in the kernel.
87 */
88
89static int parse_mount(char **);
90static struct mntarg *parse_mountroot_options(struct mntarg *, const char *);
91
92/*
93 * The vnode of the system's root (/ in the filesystem, without chroot
94 * active.)
95 */
96struct vnode *rootvnode;
97
98/*
99 * Mount of the system's /dev.
100 */
101struct mount *rootdevmp;
102
103char *rootdevnames[2] = {NULL, NULL};
104
105struct mtx root_holds_mtx;
106MTX_SYSINIT(root_holds, &root_holds_mtx, "root_holds", MTX_DEF);
107
108struct root_hold_token {
109	const char			*who;
110	LIST_ENTRY(root_hold_token)	list;
111};
112
113static LIST_HEAD(, root_hold_token)	root_holds =
114    LIST_HEAD_INITIALIZER(root_holds);
115
116enum action {
117	A_CONTINUE,
118	A_PANIC,
119	A_REBOOT,
120	A_RETRY
121};
122
123static enum action root_mount_onfail = A_CONTINUE;
124
125static int root_mount_mddev;
126static int root_mount_complete;
127
128/* By default wait up to 3 seconds for devices to appear. */
129static int root_mount_timeout = 3;
130TUNABLE_INT("vfs.mountroot.timeout", &root_mount_timeout);
131
132struct root_hold_token *
133root_mount_hold(const char *identifier)
134{
135	struct root_hold_token *h;
136
137	if (root_mounted())
138		return (NULL);
139
140	h = malloc(sizeof *h, M_DEVBUF, M_ZERO | M_WAITOK);
141	h->who = identifier;
142	mtx_lock(&root_holds_mtx);
143	LIST_INSERT_HEAD(&root_holds, h, list);
144	mtx_unlock(&root_holds_mtx);
145	return (h);
146}
147
148void
149root_mount_rel(struct root_hold_token *h)
150{
151
152	if (h == NULL)
153		return;
154	mtx_lock(&root_holds_mtx);
155	LIST_REMOVE(h, list);
156	wakeup(&root_holds);
157	mtx_unlock(&root_holds_mtx);
158	free(h, M_DEVBUF);
159}
160
161int
162root_mounted(void)
163{
164
165	/* No mutex is acquired here because int stores are atomic. */
166	return (root_mount_complete);
167}
168
169void
170root_mount_wait(void)
171{
172
173	/*
174	 * Panic on an obvious deadlock - the function can't be called from
175	 * a thread which is doing the whole SYSINIT stuff.
176	 */
177	KASSERT(curthread->td_proc->p_pid != 0,
178	    ("root_mount_wait: cannot be called from the swapper thread"));
179	mtx_lock(&root_holds_mtx);
180	while (!root_mount_complete) {
181		msleep(&root_mount_complete, &root_holds_mtx, PZERO, "rootwait",
182		    hz);
183	}
184	mtx_unlock(&root_holds_mtx);
185}
186
187static void
188set_rootvnode(void)
189{
190	struct proc *p;
191
192	if (VFS_ROOT(TAILQ_FIRST(&mountlist), LK_EXCLUSIVE, &rootvnode))
193		panic("Cannot find root vnode");
194
195	VOP_UNLOCK(rootvnode, 0);
196
197	p = curthread->td_proc;
198	FILEDESC_XLOCK(p->p_fd);
199
200	if (p->p_fd->fd_cdir != NULL)
201		vrele(p->p_fd->fd_cdir);
202	p->p_fd->fd_cdir = rootvnode;
203	VREF(rootvnode);
204
205	if (p->p_fd->fd_rdir != NULL)
206		vrele(p->p_fd->fd_rdir);
207	p->p_fd->fd_rdir = rootvnode;
208	VREF(rootvnode);
209
210	FILEDESC_XUNLOCK(p->p_fd);
211}
212
213static int
214vfs_mountroot_devfs(struct thread *td, struct mount **mpp)
215{
216	struct vfsoptlist *opts;
217	struct vfsconf *vfsp;
218	struct mount *mp;
219	int error;
220
221	*mpp = NULL;
222
223	if (rootdevmp != NULL) {
224		/*
225		 * Already have /dev; this happens during rerooting.
226		 */
227		error = vfs_busy(rootdevmp, 0);
228		if (error != 0)
229			return (error);
230		*mpp = rootdevmp;
231	} else {
232		vfsp = vfs_byname("devfs");
233		KASSERT(vfsp != NULL, ("Could not find devfs by name"));
234		if (vfsp == NULL)
235			return (ENOENT);
236
237		mp = vfs_mount_alloc(NULLVP, vfsp, "/dev", td->td_ucred);
238
239		error = VFS_MOUNT(mp);
240		KASSERT(error == 0, ("VFS_MOUNT(devfs) failed %d", error));
241		if (error)
242			return (error);
243
244		opts = malloc(sizeof(struct vfsoptlist), M_MOUNT, M_WAITOK);
245		TAILQ_INIT(opts);
246		mp->mnt_opt = opts;
247
248		mtx_lock(&mountlist_mtx);
249		TAILQ_INSERT_HEAD(&mountlist, mp, mnt_list);
250		mtx_unlock(&mountlist_mtx);
251
252		*mpp = mp;
253		rootdevmp = mp;
254	}
255
256	set_rootvnode();
257
258	error = kern_symlinkat(td, "/", AT_FDCWD, "dev", UIO_SYSSPACE);
259	if (error)
260		printf("kern_symlink /dev -> / returns %d\n", error);
261
262	return (error);
263}
264
265static void
266vfs_mountroot_shuffle(struct thread *td, struct mount *mpdevfs)
267{
268	struct nameidata nd;
269	struct mount *mporoot, *mpnroot;
270	struct vnode *vp, *vporoot, *vpdevfs;
271	char *fspath;
272	int error;
273
274	mpnroot = TAILQ_NEXT(mpdevfs, mnt_list);
275
276	/* Shuffle the mountlist. */
277	mtx_lock(&mountlist_mtx);
278	mporoot = TAILQ_FIRST(&mountlist);
279	TAILQ_REMOVE(&mountlist, mpdevfs, mnt_list);
280	if (mporoot != mpdevfs) {
281		TAILQ_REMOVE(&mountlist, mpnroot, mnt_list);
282		TAILQ_INSERT_HEAD(&mountlist, mpnroot, mnt_list);
283	}
284	TAILQ_INSERT_TAIL(&mountlist, mpdevfs, mnt_list);
285	mtx_unlock(&mountlist_mtx);
286
287	cache_purgevfs(mporoot);
288	if (mporoot != mpdevfs)
289		cache_purgevfs(mpdevfs);
290
291	VFS_ROOT(mporoot, LK_EXCLUSIVE, &vporoot);
292
293	VI_LOCK(vporoot);
294	vporoot->v_iflag &= ~VI_MOUNT;
295	VI_UNLOCK(vporoot);
296	vporoot->v_mountedhere = NULL;
297	mporoot->mnt_flag &= ~MNT_ROOTFS;
298	mporoot->mnt_vnodecovered = NULL;
299	vput(vporoot);
300
301	/* Set up the new rootvnode, and purge the cache */
302	mpnroot->mnt_vnodecovered = NULL;
303	set_rootvnode();
304	cache_purgevfs(rootvnode->v_mount);
305
306	if (mporoot != mpdevfs) {
307		/* Remount old root under /.mount or /mnt */
308		fspath = "/.mount";
309		NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
310		    fspath, td);
311		error = namei(&nd);
312		if (error) {
313			NDFREE(&nd, NDF_ONLY_PNBUF);
314			fspath = "/mnt";
315			NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE,
316			    fspath, td);
317			error = namei(&nd);
318		}
319		if (!error) {
320			vp = nd.ni_vp;
321			error = (vp->v_type == VDIR) ? 0 : ENOTDIR;
322			if (!error)
323				error = vinvalbuf(vp, V_SAVE, 0, 0);
324			if (!error) {
325				cache_purge(vp);
326				mporoot->mnt_vnodecovered = vp;
327				vp->v_mountedhere = mporoot;
328				strlcpy(mporoot->mnt_stat.f_mntonname,
329				    fspath, MNAMELEN);
330				VOP_UNLOCK(vp, 0);
331			} else
332				vput(vp);
333		}
334		NDFREE(&nd, NDF_ONLY_PNBUF);
335
336		if (error && bootverbose)
337			printf("mountroot: unable to remount previous root "
338			    "under /.mount or /mnt (error %d).\n", error);
339	}
340
341	/* Remount devfs under /dev */
342	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, "/dev", td);
343	error = namei(&nd);
344	if (!error) {
345		vp = nd.ni_vp;
346		error = (vp->v_type == VDIR) ? 0 : ENOTDIR;
347		if (!error)
348			error = vinvalbuf(vp, V_SAVE, 0, 0);
349		if (!error) {
350			vpdevfs = mpdevfs->mnt_vnodecovered;
351			if (vpdevfs != NULL) {
352				cache_purge(vpdevfs);
353				vpdevfs->v_mountedhere = NULL;
354				vrele(vpdevfs);
355			}
356			mpdevfs->mnt_vnodecovered = vp;
357			vp->v_mountedhere = mpdevfs;
358			VOP_UNLOCK(vp, 0);
359		} else
360			vput(vp);
361	}
362	if (error && bootverbose)
363		printf("mountroot: unable to remount devfs under /dev "
364		    "(error %d).\n", error);
365	NDFREE(&nd, NDF_ONLY_PNBUF);
366
367	if (mporoot == mpdevfs) {
368		vfs_unbusy(mpdevfs);
369		/* Unlink the no longer needed /dev/dev -> / symlink */
370		error = kern_unlinkat(td, AT_FDCWD, "/dev/dev",
371		    UIO_SYSSPACE, 0);
372		if (error && bootverbose)
373			printf("mountroot: unable to unlink /dev/dev "
374			    "(error %d)\n", error);
375	}
376}
377
378/*
379 * Configuration parser.
380 */
381
382/* Parser character classes. */
383#define	CC_WHITESPACE		-1
384#define	CC_NONWHITESPACE	-2
385
386/* Parse errors. */
387#define	PE_EOF			-1
388#define	PE_EOL			-2
389
390static __inline int
391parse_peek(char **conf)
392{
393
394	return (**conf);
395}
396
397static __inline void
398parse_poke(char **conf, int c)
399{
400
401	**conf = c;
402}
403
404static __inline void
405parse_advance(char **conf)
406{
407
408	(*conf)++;
409}
410
411static int
412parse_skipto(char **conf, int mc)
413{
414	int c, match;
415
416	while (1) {
417		c = parse_peek(conf);
418		if (c == 0)
419			return (PE_EOF);
420		switch (mc) {
421		case CC_WHITESPACE:
422			match = (c == ' ' || c == '\t' || c == '\n') ? 1 : 0;
423			break;
424		case CC_NONWHITESPACE:
425			if (c == '\n')
426				return (PE_EOL);
427			match = (c != ' ' && c != '\t') ? 1 : 0;
428			break;
429		default:
430			match = (c == mc) ? 1 : 0;
431			break;
432		}
433		if (match)
434			break;
435		parse_advance(conf);
436	}
437	return (0);
438}
439
440static int
441parse_token(char **conf, char **tok)
442{
443	char *p;
444	size_t len;
445	int error;
446
447	*tok = NULL;
448	error = parse_skipto(conf, CC_NONWHITESPACE);
449	if (error)
450		return (error);
451	p = *conf;
452	error = parse_skipto(conf, CC_WHITESPACE);
453	len = *conf - p;
454	*tok = malloc(len + 1, M_TEMP, M_WAITOK | M_ZERO);
455	bcopy(p, *tok, len);
456	return (0);
457}
458
459static void
460parse_dir_ask_printenv(const char *var)
461{
462	char *val;
463
464	val = kern_getenv(var);
465	if (val != NULL) {
466		printf("  %s=%s\n", var, val);
467		freeenv(val);
468	}
469}
470
471static int
472parse_dir_ask(char **conf)
473{
474	char name[80];
475	char *mnt;
476	int error;
477
478	printf("\nLoader variables:\n");
479	parse_dir_ask_printenv("vfs.root.mountfrom");
480	parse_dir_ask_printenv("vfs.root.mountfrom.options");
481
482	printf("\nManual root filesystem specification:\n");
483	printf("  <fstype>:<device> [options]\n");
484	printf("      Mount <device> using filesystem <fstype>\n");
485	printf("      and with the specified (optional) option list.\n");
486	printf("\n");
487	printf("    eg. ufs:/dev/da0s1a\n");
488	printf("        zfs:tank\n");
489	printf("        cd9660:/dev/acd0 ro\n");
490	printf("          (which is equivalent to: ");
491	printf("mount -t cd9660 -o ro /dev/acd0 /)\n");
492	printf("\n");
493	printf("  ?               List valid disk boot devices\n");
494	printf("  .               Yield 1 second (for background tasks)\n");
495	printf("  <empty line>    Abort manual input\n");
496
497	do {
498		error = EINVAL;
499		printf("\nmountroot> ");
500		cngets(name, sizeof(name), GETS_ECHO);
501		if (name[0] == '\0')
502			break;
503		if (name[0] == '?' && name[1] == '\0') {
504			printf("\nList of GEOM managed disk devices:\n  ");
505			g_dev_print();
506			continue;
507		}
508		if (name[0] == '.' && name[1] == '\0') {
509			pause("rmask", hz);
510			continue;
511		}
512		mnt = name;
513		error = parse_mount(&mnt);
514		if (error == -1)
515			printf("Invalid file system specification.\n");
516	} while (error != 0);
517
518	return (error);
519}
520
521static int
522parse_dir_md(char **conf)
523{
524	struct stat sb;
525	struct thread *td;
526	struct md_ioctl *mdio;
527	char *path, *tok;
528	int error, fd, len;
529
530	td = curthread;
531
532	error = parse_token(conf, &tok);
533	if (error)
534		return (error);
535
536	len = strlen(tok);
537	mdio = malloc(sizeof(*mdio) + len + 1, M_TEMP, M_WAITOK | M_ZERO);
538	path = (void *)(mdio + 1);
539	bcopy(tok, path, len);
540	free(tok, M_TEMP);
541
542	/* Get file status. */
543	error = kern_statat(td, 0, AT_FDCWD, path, UIO_SYSSPACE, &sb, NULL);
544	if (error)
545		goto out;
546
547	/* Open /dev/mdctl so that we can attach/detach. */
548	error = kern_openat(td, AT_FDCWD, "/dev/" MDCTL_NAME, UIO_SYSSPACE,
549	    O_RDWR, 0);
550	if (error)
551		goto out;
552
553	fd = td->td_retval[0];
554	mdio->md_version = MDIOVERSION;
555	mdio->md_type = MD_VNODE;
556
557	if (root_mount_mddev != -1) {
558		mdio->md_unit = root_mount_mddev;
559		DROP_GIANT();
560		error = kern_ioctl(td, fd, MDIOCDETACH, (void *)mdio);
561		PICKUP_GIANT();
562		/* Ignore errors. We don't care. */
563		root_mount_mddev = -1;
564	}
565
566	mdio->md_file = (void *)(mdio + 1);
567	mdio->md_options = MD_AUTOUNIT | MD_READONLY;
568	mdio->md_mediasize = sb.st_size;
569	mdio->md_unit = 0;
570	DROP_GIANT();
571	error = kern_ioctl(td, fd, MDIOCATTACH, (void *)mdio);
572	PICKUP_GIANT();
573	if (error)
574		goto out;
575
576	if (mdio->md_unit > 9) {
577		printf("rootmount: too many md units\n");
578		mdio->md_file = NULL;
579		mdio->md_options = 0;
580		mdio->md_mediasize = 0;
581		DROP_GIANT();
582		error = kern_ioctl(td, fd, MDIOCDETACH, (void *)mdio);
583		PICKUP_GIANT();
584		/* Ignore errors. We don't care. */
585		error = ERANGE;
586		goto out;
587	}
588
589	root_mount_mddev = mdio->md_unit;
590	printf(MD_NAME "%u attached to %s\n", root_mount_mddev, mdio->md_file);
591
592	error = kern_close(td, fd);
593
594 out:
595	free(mdio, M_TEMP);
596	return (error);
597}
598
599static int
600parse_dir_onfail(char **conf)
601{
602	char *action;
603	int error;
604
605	error = parse_token(conf, &action);
606	if (error)
607		return (error);
608
609	if (!strcmp(action, "continue"))
610		root_mount_onfail = A_CONTINUE;
611	else if (!strcmp(action, "panic"))
612		root_mount_onfail = A_PANIC;
613	else if (!strcmp(action, "reboot"))
614		root_mount_onfail = A_REBOOT;
615	else if (!strcmp(action, "retry"))
616		root_mount_onfail = A_RETRY;
617	else {
618		printf("rootmount: %s: unknown action\n", action);
619		error = EINVAL;
620	}
621
622	free(action, M_TEMP);
623	return (0);
624}
625
626static int
627parse_dir_timeout(char **conf)
628{
629	char *tok, *endtok;
630	long secs;
631	int error;
632
633	error = parse_token(conf, &tok);
634	if (error)
635		return (error);
636
637	secs = strtol(tok, &endtok, 0);
638	error = (secs < 0 || *endtok != '\0') ? EINVAL : 0;
639	if (!error)
640		root_mount_timeout = secs;
641	free(tok, M_TEMP);
642	return (error);
643}
644
645static int
646parse_directive(char **conf)
647{
648	char *dir;
649	int error;
650
651	error = parse_token(conf, &dir);
652	if (error)
653		return (error);
654
655	if (strcmp(dir, ".ask") == 0)
656		error = parse_dir_ask(conf);
657	else if (strcmp(dir, ".md") == 0)
658		error = parse_dir_md(conf);
659	else if (strcmp(dir, ".onfail") == 0)
660		error = parse_dir_onfail(conf);
661	else if (strcmp(dir, ".timeout") == 0)
662		error = parse_dir_timeout(conf);
663	else {
664		printf("mountroot: invalid directive `%s'\n", dir);
665		/* Ignore the rest of the line. */
666		(void)parse_skipto(conf, '\n');
667		error = EINVAL;
668	}
669	free(dir, M_TEMP);
670	return (error);
671}
672
673static int
674parse_mount_dev_present(const char *dev)
675{
676	struct nameidata nd;
677	int error;
678
679	NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF, UIO_SYSSPACE, dev, curthread);
680	error = namei(&nd);
681	if (!error)
682		vput(nd.ni_vp);
683	NDFREE(&nd, NDF_ONLY_PNBUF);
684	return (error != 0) ? 0 : 1;
685}
686
687#define	ERRMSGL	255
688static int
689parse_mount(char **conf)
690{
691	char *errmsg;
692	struct mntarg *ma;
693	char *dev, *fs, *opts, *tok;
694	int delay, error, timeout;
695
696	error = parse_token(conf, &tok);
697	if (error)
698		return (error);
699	fs = tok;
700	error = parse_skipto(&tok, ':');
701	if (error) {
702		free(fs, M_TEMP);
703		return (error);
704	}
705	parse_poke(&tok, '\0');
706	parse_advance(&tok);
707	dev = tok;
708
709	if (root_mount_mddev != -1) {
710		/* Handle substitution for the md unit number. */
711		tok = strstr(dev, "md#");
712		if (tok != NULL)
713			tok[2] = '0' + root_mount_mddev;
714	}
715
716	/* Parse options. */
717	error = parse_token(conf, &tok);
718	opts = (error == 0) ? tok : NULL;
719
720	printf("Trying to mount root from %s:%s [%s]...\n", fs, dev,
721	    (opts != NULL) ? opts : "");
722
723	errmsg = malloc(ERRMSGL, M_TEMP, M_WAITOK | M_ZERO);
724
725	if (vfs_byname(fs) == NULL) {
726		strlcpy(errmsg, "unknown file system", ERRMSGL);
727		error = ENOENT;
728		goto out;
729	}
730
731	if (strcmp(fs, "zfs") != 0 && strstr(fs, "nfs") == NULL &&
732	    dev[0] != '\0' && !parse_mount_dev_present(dev)) {
733		printf("mountroot: waiting for device %s ...\n", dev);
734		delay = hz / 10;
735		timeout = root_mount_timeout * hz;
736		do {
737			pause("rmdev", delay);
738			timeout -= delay;
739		} while (timeout > 0 && !parse_mount_dev_present(dev));
740		if (timeout <= 0) {
741			error = ENODEV;
742			goto out;
743		}
744	}
745
746	ma = NULL;
747	ma = mount_arg(ma, "fstype", fs, -1);
748	ma = mount_arg(ma, "fspath", "/", -1);
749	ma = mount_arg(ma, "from", dev, -1);
750	ma = mount_arg(ma, "errmsg", errmsg, ERRMSGL);
751	ma = mount_arg(ma, "ro", NULL, 0);
752	ma = parse_mountroot_options(ma, opts);
753	error = kernel_mount(ma, MNT_ROOTFS);
754
755 out:
756	if (error) {
757		printf("Mounting from %s:%s failed with error %d",
758		    fs, dev, error);
759		if (errmsg[0] != '\0')
760			printf(": %s", errmsg);
761		printf(".\n");
762	}
763	free(fs, M_TEMP);
764	free(errmsg, M_TEMP);
765	if (opts != NULL)
766		free(opts, M_TEMP);
767	/* kernel_mount can return -1 on error. */
768	return ((error < 0) ? EDOOFUS : error);
769}
770#undef ERRMSGL
771
772static int
773vfs_mountroot_parse(struct sbuf *sb, struct mount *mpdevfs)
774{
775	struct mount *mp;
776	char *conf;
777	int error;
778
779	root_mount_mddev = -1;
780
781retry:
782	conf = sbuf_data(sb);
783	mp = TAILQ_NEXT(mpdevfs, mnt_list);
784	error = (mp == NULL) ? 0 : EDOOFUS;
785	root_mount_onfail = A_CONTINUE;
786	while (mp == NULL) {
787		error = parse_skipto(&conf, CC_NONWHITESPACE);
788		if (error == PE_EOL) {
789			parse_advance(&conf);
790			continue;
791		}
792		if (error < 0)
793			break;
794		switch (parse_peek(&conf)) {
795		case '#':
796			error = parse_skipto(&conf, '\n');
797			break;
798		case '.':
799			error = parse_directive(&conf);
800			break;
801		default:
802			error = parse_mount(&conf);
803			if (error == -1) {
804				printf("mountroot: invalid file system "
805				    "specification.\n");
806				error = 0;
807			}
808			break;
809		}
810		if (error < 0)
811			break;
812		/* Ignore any trailing garbage on the line. */
813		if (parse_peek(&conf) != '\n') {
814			printf("mountroot: advancing to next directive...\n");
815			(void)parse_skipto(&conf, '\n');
816		}
817		mp = TAILQ_NEXT(mpdevfs, mnt_list);
818	}
819	if (mp != NULL)
820		return (0);
821
822	/*
823	 * We failed to mount (a new) root.
824	 */
825	switch (root_mount_onfail) {
826	case A_CONTINUE:
827		break;
828	case A_PANIC:
829		panic("mountroot: unable to (re-)mount root.");
830		/* NOTREACHED */
831	case A_RETRY:
832		goto retry;
833	case A_REBOOT:
834		kern_reboot(RB_NOSYNC);
835		/* NOTREACHED */
836	}
837
838	return (error);
839}
840
841static void
842vfs_mountroot_conf0(struct sbuf *sb)
843{
844	char *s, *tok, *mnt, *opt;
845	int error;
846
847	sbuf_printf(sb, ".onfail panic\n");
848	sbuf_printf(sb, ".timeout %d\n", root_mount_timeout);
849	if (boothowto & RB_ASKNAME)
850		sbuf_printf(sb, ".ask\n");
851#ifdef ROOTDEVNAME
852	if (boothowto & RB_DFLTROOT)
853		sbuf_printf(sb, "%s\n", ROOTDEVNAME);
854#endif
855	if (boothowto & RB_CDROM) {
856		sbuf_printf(sb, "cd9660:/dev/cd0 ro\n");
857		sbuf_printf(sb, ".timeout 0\n");
858		sbuf_printf(sb, "cd9660:/dev/acd0 ro\n");
859		sbuf_printf(sb, ".timeout %d\n", root_mount_timeout);
860	}
861	s = kern_getenv("vfs.root.mountfrom");
862	if (s != NULL) {
863		opt = kern_getenv("vfs.root.mountfrom.options");
864		tok = s;
865		error = parse_token(&tok, &mnt);
866		while (!error) {
867			sbuf_printf(sb, "%s %s\n", mnt,
868			    (opt != NULL) ? opt : "");
869			free(mnt, M_TEMP);
870			error = parse_token(&tok, &mnt);
871		}
872		if (opt != NULL)
873			freeenv(opt);
874		freeenv(s);
875	}
876	if (rootdevnames[0] != NULL)
877		sbuf_printf(sb, "%s\n", rootdevnames[0]);
878	if (rootdevnames[1] != NULL)
879		sbuf_printf(sb, "%s\n", rootdevnames[1]);
880#ifdef ROOTDEVNAME
881	if (!(boothowto & RB_DFLTROOT))
882		sbuf_printf(sb, "%s\n", ROOTDEVNAME);
883#endif
884	if (!(boothowto & RB_ASKNAME))
885		sbuf_printf(sb, ".ask\n");
886}
887
888static int
889vfs_mountroot_readconf(struct thread *td, struct sbuf *sb)
890{
891	static char buf[128];
892	struct nameidata nd;
893	off_t ofs;
894	ssize_t resid;
895	int error, flags, len;
896
897	NDINIT(&nd, LOOKUP, FOLLOW, UIO_SYSSPACE, "/.mount.conf", td);
898	flags = FREAD;
899	error = vn_open(&nd, &flags, 0, NULL);
900	if (error)
901		return (error);
902
903	NDFREE(&nd, NDF_ONLY_PNBUF);
904	ofs = 0;
905	len = sizeof(buf) - 1;
906	while (1) {
907		error = vn_rdwr(UIO_READ, nd.ni_vp, buf, len, ofs,
908		    UIO_SYSSPACE, IO_NODELOCKED, td->td_ucred,
909		    NOCRED, &resid, td);
910		if (error)
911			break;
912		if (resid == len)
913			break;
914		buf[len - resid] = 0;
915		sbuf_printf(sb, "%s", buf);
916		ofs += len - resid;
917	}
918
919	VOP_UNLOCK(nd.ni_vp, 0);
920	vn_close(nd.ni_vp, FREAD, td->td_ucred, td);
921	return (error);
922}
923
924static void
925vfs_mountroot_wait(void)
926{
927	struct root_hold_token *h;
928	struct timeval lastfail;
929	int curfail;
930
931	curfail = 0;
932	while (1) {
933		DROP_GIANT();
934		g_waitidle();
935		PICKUP_GIANT();
936		mtx_lock(&root_holds_mtx);
937		if (LIST_EMPTY(&root_holds)) {
938			mtx_unlock(&root_holds_mtx);
939			break;
940		}
941		if (ppsratecheck(&lastfail, &curfail, 1)) {
942			printf("Root mount waiting for:");
943			LIST_FOREACH(h, &root_holds, list)
944				printf(" %s", h->who);
945			printf("\n");
946		}
947		msleep(&root_holds, &root_holds_mtx, PZERO | PDROP, "roothold",
948		    hz);
949	}
950}
951
952void
953vfs_mountroot(void)
954{
955	struct mount *mp;
956	struct sbuf *sb;
957	struct thread *td;
958	time_t timebase;
959	int error;
960
961	td = curthread;
962
963	vfs_mountroot_wait();
964
965	sb = sbuf_new_auto();
966	vfs_mountroot_conf0(sb);
967	sbuf_finish(sb);
968
969	error = vfs_mountroot_devfs(td, &mp);
970	while (!error) {
971		error = vfs_mountroot_parse(sb, mp);
972		if (!error) {
973			vfs_mountroot_shuffle(td, mp);
974			sbuf_clear(sb);
975			error = vfs_mountroot_readconf(td, sb);
976			sbuf_finish(sb);
977		}
978	}
979
980	sbuf_delete(sb);
981
982	/*
983	 * Iterate over all currently mounted file systems and use
984	 * the time stamp found to check and/or initialize the RTC.
985	 * Call inittodr() only once and pass it the largest of the
986	 * timestamps we encounter.
987	 */
988	timebase = 0;
989	mtx_lock(&mountlist_mtx);
990	mp = TAILQ_FIRST(&mountlist);
991	while (mp != NULL) {
992		if (mp->mnt_time > timebase)
993			timebase = mp->mnt_time;
994		mp = TAILQ_NEXT(mp, mnt_list);
995	}
996	mtx_unlock(&mountlist_mtx);
997	inittodr(timebase);
998
999	/* Keep prison0's root in sync with the global rootvnode. */
1000	mtx_lock(&prison0.pr_mtx);
1001	prison0.pr_root = rootvnode;
1002	vref(prison0.pr_root);
1003	mtx_unlock(&prison0.pr_mtx);
1004
1005	mtx_lock(&root_holds_mtx);
1006	atomic_store_rel_int(&root_mount_complete, 1);
1007	wakeup(&root_mount_complete);
1008	mtx_unlock(&root_holds_mtx);
1009
1010	EVENTHANDLER_INVOKE(mountroot);
1011}
1012
1013static struct mntarg *
1014parse_mountroot_options(struct mntarg *ma, const char *options)
1015{
1016	char *p;
1017	char *name, *name_arg;
1018	char *val, *val_arg;
1019	char *opts;
1020
1021	if (options == NULL || options[0] == '\0')
1022		return (ma);
1023
1024	p = opts = strdup(options, M_MOUNT);
1025	if (opts == NULL) {
1026		return (ma);
1027	}
1028
1029	while((name = strsep(&p, ",")) != NULL) {
1030		if (name[0] == '\0')
1031			break;
1032
1033		val = strchr(name, '=');
1034		if (val != NULL) {
1035			*val = '\0';
1036			++val;
1037		}
1038		if( strcmp(name, "rw") == 0 ||
1039		    strcmp(name, "noro") == 0) {
1040			/*
1041			 * The first time we mount the root file system,
1042			 * we need to mount 'ro', so We need to ignore
1043			 * 'rw' and 'noro' mount options.
1044			 */
1045			continue;
1046		}
1047		name_arg = strdup(name, M_MOUNT);
1048		val_arg = NULL;
1049		if (val != NULL)
1050			val_arg = strdup(val, M_MOUNT);
1051
1052		ma = mount_arg(ma, name_arg, val_arg,
1053		    (val_arg != NULL ? -1 : 0));
1054	}
1055	free(opts, M_MOUNT);
1056	return (ma);
1057}
1058